Multivibrator saw-tooth generator



y 29, 1952 E. H. B. BARTELINK ET AL 2,605,406

MULTIVIBRATOR SAW TOOTH GENERATOR Filed Dec. 12, 1945 F lG.l

SAWTOOTH OUTPUT M NEGATIVE GATE POSITIVE g? GATE 33 2s L/34 39 SYNCH.

TRIGGERS NEGATIVE gLERO VOLTAGE TUBE lo {CUT-OFF GRID VOLTAGE SAWTOOTH OUTPUT VOLTAGE g ZERO VOLTAGE TUBEH I T GRID CUT OFF VOLTAGE INVENTORS EVERHARD H. B. BARTELINK STANLEY W. TORODE BY RALPH J. WALKER ATTORNEY v phase relationships.

Patented July 29, 1952 I MULTIVIBRATOR SAW-TOOTH GE ERATOR Y 1 Everhard H. B. Bartelink and Stanley W. Torode,

, Cambridge, Mass., and Ralph J. Walker, Washington, D. 0., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Application December 12, 1945, Serial No.634l,51 6 7 3 Claims. (01. 250 -27),

This invention relatesto'sawtooth wave generators and more particularly to a combination of a multivibrator and resistor-capacitor network that provides-synchronously and independently a sawtooth wave and positive and negative g atesa Gate producing multivibrators and many types I 1 of sawtooth generators are well known in the arti; Howeve'r separate circuits are needed foreach purpose as well as 1 additional circuits for achieving sychronism between gates and sawtooth; I v

The present invention provides in a single integrated 'circuita greatly simplified means of furnishing synchronous gates and a sawtooth wave;

An objectof this invention is to provide in one simple circuit a combination gate and sawtooth Wave generator. iAnoth'erzobject is to control the cyclical frequency of the gate and sawtooth wave generator by means of synchronizing triggers.

Another object is to employ a multivibrator asithe device for controlling the charge and dischargeof a' resistor-capacitor network to produce a saw-tooth wave.

These and other objects and features of this invention will become apparent upon a considerationof the following detailed description when taken'together with the acompanying drawings, the figures or which illustrate a typical embodiment of this'invention.

'Fi'g.1"is a circuit diagram of the multivibrator withthe associated resistor-capacitor network forthe' sawtooth output.-

illustrates the waveforms' at various points of {the circuit of Figure 1 in their proper In'Fi'g. 1, tubes m an'd u are the two stages of a mul tivibrator. Positive'potential at point I 2. i's'supplied tdthe' plate of tube I 0 through resistor IB' and to the plate of tube II through resistor I'!. The controlgrid of tube II is biased from :I 2;:th 0l1gh resistors I8 and I 9 in series. The

sistor'ZS; I Resistor 30, capacitor 3| and resistor :32 are in series across resistor 29, and resistor 33fconnects' between the junction of (H and 32 point-34 at which synchronizing triggers '39 are'fintroduced. Resistors 32 and 33' provide voltage division to adjust the synchronizing triggers 39 to the desired value.

Resistor 36 and capacitor 31 are in series between the: plate of tube I0 and ground and provide the sawtooth output voltage ;4I at point 38. "In Fig. 2 the negative triggers 3$I are those applied at 34'to the cathode circuit of tube 10. Voltage wave form 40 appears at the grid of tube I0. Wave form M is that of the sawtooth output voltage at point 38. Voltage wave form 42 appears at-the grid of tube II. H

The natural frequency of the multivibrator is chiefly controlledby the time constant of the capacitor-21 and the resistor I8, which is large compared to resistor I9, by .the time constant of the capacitor 26 and the resistor '20, by the voltage appearing at the top endof resistor I8, and by the voltage appearing" atthe slider .arm 2| The capacitor 21 and esistor I8 control the time constant of thegrid of tube I I and thus the time tube I I is nonc'onducting. The capacitor 26 and resistor 20 as well as. the voltage at 2I control the time constant of the grid of tube I0 and thus control the time tube I0 is non-conducting.

Negative and positive gates inphase opposition appear at the plate and. cathode of tube I.I respectivelyduring the conducting period of tube II, the negative gate being opposed. in phase to wave form 42 at the grid of tube I I and the positive gate beingin phase with wave form 42.

When tube I I starts to conduct, tube I0 is cutoff and capacitor, 31 ischarged towards the potential at I2 through resistors I6 and 3 6 in series. This forms the upward sweep of sawtooth output' voltage wave formJII. When the multivibrator reverses, tube II cutsoff as shown in the negative pulse of wave 42, ending the positive and negative gates. Tube I0 begins to conduct and forms a low resistance discharge path for capacitor ,3! in series with resisto'rs 36 and 29. The voltage on capacitor. 31. then sweeps downward relatively rapidly 'compared to the voltage rise on charging through the large resistor I6. Thus the sawtooth output voltage waveform AI is formed sweeping upward synchronously with 'the positive and negative gates from tube I I and returning rapidly to the start ing point when the gates cease. I It willbe noted thatwhen tube I 0 conducts it eifectively receives its plate potential fromcapacitor 31 and resisto'r 36 acts as the plate resistor. Capacitor 31 and resistor 36 are such in value that the voltage supplied to the plate of tube' I0 varies but 10 percent.

The cylical frequency of the multivilcuator can be synchronized to the frequency of the synchronizing triggers 39 or sub-multiples thereof, when the time that'the grid of tube I0 is cutoff is greater than the period of the synchronizing triggers. Frequency division results from the fact that the grid of tube I0 is driven so far negative as shown in 49 that the negative triggers 3901c the cathode of IO are insuflicient to make the tube conduct. By adjusting the voltag at 2 I, the'cut off time of the grid of tube I0 can be 3 varied so that, for instance, the grid is still far below cut off when the second negative trigger arrives but is almost back to cut off when the third negative trigger arrives, causing the tube to fire and trip the multivibrator. The voltage at 2] and the grid circuit time constant can be adjusted so that tube I fires on th first, second or subsequent triggers to providea cyclical fre-' quency of the multivibrator which is equal to or a sub-multiple of the synchronizing frequency.

Although there is shown and described only a certain specific embodiment of multivibrator sawtooth generator, the-many modifications possible thereof will be readily apparent to those familiar with th'e'art. Therefore this invention 'isfnot "to be'limite'd except'insofar as is necessitated by the prior art and the spirit of the appended claims. jj What is claimed is:

1; A circuit for the synchronous generation of a sawtooth voltage wave with positive and negativevoltagesquare waves comprising, a multiyibrator including first and second electron tubes, each of said tubes having a cathode, an anode and facontrol grid, means forcoupling the anode of ea'ch of said tubes to the controlgrid of the other tube, a source of potential to energize said multivibrator, anode and cathode resistors for connecting each of said tubes individually to said potentialfsource, means'for connecting the control, grid of saidfirst' tube to said potential source, to bias said first tube to be normally conducting, means for connecting the control grid of Isaid second tube to said potential source to bias, said second tube to be normally nonconducting, a storage capacitor and a series resistor connected to shunt said second tube between the anode .of said second tube and the end of the cathode resistor of said tube remote the cathode thereof, a source of synchronizing pulses having apredetermined repetition rate, means for applying pulses from said source to bias said second tube'to conduction therebyterminating the conduction of said first tube fora time interval determined by the time constant of the grid circuit of said first tube, whereby said storage capacitor charges. relatively slowly from said potential source during nonconduction of said second tube and discharges relatively rapidly during conduction. of said second tube while termination of conduction of said first tube terminates a negativejoltage square wave at, the anode thereof and a positive voltage square wave at the oatho'de.thereof.. I 2. A circuit for the synchronous generation of a sawtooth voltage wave with positive and negative voltage squarelwaves comprising, a multivibrator including first and second electron tubes, eachof saidv tubes havinga cathode, an anode andacontrol grid, means for coupling the anode of each ofsaid tubes to the control grid of the other tube, a source of potential to energize said multivibrator, anode and cathode resistors for connecting each of said tubes individually to said potential source, means for connecting the control gridv of 'said'first tube to said potential source to bias said firsttube to be normally conducting, means forconnecting the control grid o fsaid second tube to said potential source to bias saidsecond-tube to be normally nonconducting, a storage capacitor and a series resistor connected to shunt said second tube between the anode of said second tube and the end of the cathode resistor of said/cube remote the cathode 4 thereof, a source of synchronizingpulses having a predetermined repetition rate, the grid circuit of said second tube having a time constant to provide a multivibrator frequency at the fre- .quency of .said synchronizing pulses, means for applying pulses from said source to bias said second tube to conduction thereby terminating the conduction of said first tube for a time interval determined b the time constant of the grid circuit of said first tube, whereby aid storage capacitor charges relatively slowly from said potential source during nonconduction of said second tube and discharges relatively rapidly during conduction of said second tube while termination of conduction of saidfirst tube terminates a negative voltage square wave at the anode thereof and a positive squarewave at the cathode thereof.

3. A circuit for the synchronous ,generation'of a sawtooth voltage wave with positive and negative voltage square waves comprising, a multivibrator including first and'second electron tubes, each of said tubes having a cathode, an anode and a control grid, means for coupling the anode of each of said tubes to the control grid of the other tube, a source of potential to energize said multivibrator, anode and cathode resistors for connecting each of said tubes individually to said potential source, means for connectin the control rid of said first tube to said potential source to bias said first tube to be normally conducting, means for connecting the control grid of said second tube to said potential source to bia said second tube to be normally nonconducting, a storage capacitor and a series resistor connected to shunt said second tube between the anode of said second tube and the end of the cathode resistor of said tube'remote the cathode thereof, a source of synchronizing pulses having a predetermined repetition rate, means to adjust the bias of said second tube to provide a multivi brator frequency at a predetermined submultiple of the frequency of said synchronizing pulses, means for applying pulses from said source to bias said second tube to conduction thereby terminating the conduction of said first tube for a. time interval determined by the time constant of the grid circuit of saidfirstv tube, whereby said storage capacitor charges relatively slowly from said potential source during nonconduction of said second tube and discharges relatively rapidlyduring conduction of said second tube while termination of conduction of said first tube terminates a negative voltage square wave at the anode thereof and a positive voltage square wave at-the cathode thereof.

EVERHARD BARTELINK, STANLEY W. TORODE. RALPH J. WALKER.

REFERENCES CITED Thefollowing references are of recordin the file of this patent: V

UNITED STATES PATENTS Number Name Date 2,114,938 Puckle Apr. 19, 1938 2,155,210 Young Apr. 18, 1939 2,157,434 Potter May 9, 1939 2,193,850 Anorieu et a1 Mar. 19, 1940 2,195,972 Pieplow Apr. 2, 1940 2,241,619 Sherman May 13, 1941 2,459,723 Shantz June 18, 949 2,523,763 Jacob Sept. 26, 1950 

